Pneumatic dispatch-tube



(No Model.)

D HUNTER PNEUMATIC DISPATCH TUBE. v No. 461,612. Patented Oot.Z0,1891.

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TE s co., mom-um UNITED STATES PATE T- OFFICE;

DAVID HUNTER, OF MINNEAPOLIS, MINNESOTA.-

PNEUMATIC DISPATCH-TUBE.-

SPEGIFICATION forming part Of Letters Patent No. 461,612, dated October 20, 1891.

Application filed May 7, 1891. Serial No. 391,969. (No model.)

To all whom it may concern.-

Be it known that I, DAVID HUNTER, a citizen of the United States, residing at Minne- I have illustrated the application of my in- 'nected with the main tube B by a union'?),

vention in the accompanying drawings, therein likeletters referring to like parts throughout.

Figure l is a side elevation of a system of dispatch-tubes equipped with my impr'ovement; and Fig. 2 is an enlarged view of the discharge end of the pneumatic tube, some parts being broken away.

A A A represent the floor-levels of a building.

B, B, O, D, and E represent a system of pneumatic tubes, of the ordinary and wellknown construction.

F is a steam-supply pipe in communication with a source of steam which enters the pneumatic tube at some convenient point, and has its discharge-nozzle F located in the discharge-section B of the tube. The steampipe is provided with a hand-valve f.

Gis the expansion-chamber, attached to the end of the section B of the pneumatic tube and terminating in the chimney or stack H.

The operat on is evident. The movement of the steam worn the nozzle F through the dischargesectipn B, the expansion-chamber G, and the chimney II will produce a partial vacuum in the other parts of the pneumatic tubes behind the nozzle F. It will be noted that the steam-nozzle F is an ordinary jetnozzle, requiring little or no special fitting and enabling the production of the vacuum by the use of very little steam. By my plan, where steam plants are employed in the building, as is very generally the case, especially in newspaper printing-offices and similar establishments, practically no additional space is required beyond that occupied by the pneumatictube, and the amount of steam consumed to effect and keep up the vacuum is scarcely appreciable on the boiler. By actual usageI have demonstrated the efficiency and economy of this invention.

The discharge-section B is preferably contelescoping on the section B and connected with the end of section B by a screw-threaded joint I). This affords a convenient means for connecting and disconnecting the dischargesection and steam-pipe and expansion-chamber from the main pipe, and also affords a means of adapting the discharge-section to different locations or positions of the main pipe with reference to the chimney or stack.

What I claim, and desire to secure by Letters Patent of the United States, is as follows:

In a pneumatic dispatch system, the com bination, with the two fixed sections of the draft-tube,-of the removable connecting section or union 1), telescoping on one of the fixed sections and having a screw-threaded engagement with the other,'substantially as described.

In testimony whereo flaifix mysignature in presence of two witnesses.

DAVID HUNTER.

Witnesses:

J AS. F. WILLIAMSON, E. F. ELMORE. 

